001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.util;
019
020import java.io.Serializable;
021import java.util.EventListener;
022import java.util.Iterator;
023import java.util.concurrent.CopyOnWriteArrayList;
024
025/**
026 */
027
028public class ListenerList implements Serializable, Iterable<EventListener>
029{
030    private static final long serialVersionUID = -1934227607974228213L;
031
032    private final CopyOnWriteArrayList<EventListener> __listeners;
033
034    public ListenerList()
035    {
036        __listeners = new CopyOnWriteArrayList<EventListener>();
037    }
038
039    public void addListener(EventListener listener)
040    {
041            __listeners.add(listener);
042    }
043
044    public  void removeListener(EventListener listener)
045    {
046            __listeners.remove(listener);
047    }
048
049    public int getListenerCount()
050    {
051        return __listeners.size();
052    }
053
054    /**
055     * Return an {@link Iterator} for the {@link EventListener} instances.
056     *
057     * @return an {@link Iterator} for the {@link EventListener} instances
058     * @since 2.0
059     * TODO Check that this is a good defensive strategy
060     */
061    @Override
062    public Iterator<EventListener> iterator() {
063            return __listeners.iterator();
064    }
065
066}